How To: Install a Mortar Shower Pan

Mark Donovan is remodeling a ceramic tile shower, and shows how to install a mortar shower pan. First consider the framing of the shower. Plywood, 2x4's and 2x6's provide a good foundation for the weight of the tile. Then remove the cover from the drain. Use duct tape to cover the drain hole. Staple 15-pound felt paper onto the floor of the shower, and up about an inch on the sides, trimming around the drain, to protect the wood from moisture. Then staple down metal lath to reinforce the floor and provide a foundation for the mortar. Mix and trowel mortar into the shower pan to provide a nice drain slope. Let the mortar set overnight. Then add felt paper to the rest of the shower. Install waterproof membrane liner to the shower pan, folding at the back corners and nailing about 6 inches above the floor, then cut out the drain hole. Use caulk to seal the membrane around the drain hole. Staple the front of the membrane to the outside to the shower curb to prevent leaks. Install tile backer board to the shower walls, rough side out, leaving an inch of space at the bottom. Seal all seams with silicone caulk. Trowel and smooth a second layer of mortar, then let it set 24-48 hours. Finally you'll be ready to add the ceramic tile.